西安地区全新世气候变化与土壤侵蚀研究  

Climate Change and Soil Erosion in Holocene in Xi’an Area

作　　者：周旗[1,2] 赵景波 苏敏[4] 王晓宁 马延东 楚纯洁 ZHOU Qi;ZHAO Jingbo;SU Min;WANG Xiaoning;MA Yandong;CHU Chunjie(Shaanxi key Laboratory of Disasters Monitoring and Mechanism Simulation,Baoji University of Arts and Sciences,Baoji,Shaanxi 721013,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,Shaanxi,China;Key Laboratory of Aerosol Chemistry and Physics,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,Shaanxi,China;School of Geography and tourism,Shaanxi Normal University,Xi’an 710062,Shaanxi,China;Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region(Chang’an University),Ministry of Education,Xi’an,710054,Shaanxi,China;School of resources and environment,Pingdingshan University,Pingdingshan,Henan 467000,China)

机构地区：[1]宝鸡文理学院陕西省灾害监测与机理模拟重点实验室,陕西宝鸡721013 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [3]中国科学院地球环境研究所气溶胶化学与物理重点实验室,西安710061 [4]陕西师范大学地理科学与旅游学院,西安710062 [5]长安大学干旱区地表水文和生态效应教育部重点实验室,西安710054 [6]平顶山学院资源与环境科学学院,河南平顶山467000

出　　处：《土壤学报》2021年第6期1404-1415,共12页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41930641,41771215);中国科学院气溶胶化学与物理重点实验室项目(KLACP-1904);黄土与第四纪地质国家重点实验室项目(SKLLQG2013)资助。

摘　　要：为了揭示西安地区全新世环境变化和黄土地层的侵蚀期,利用野外调查和化学分析等方法,研究了西安地区全新世黄土与古土壤发育时的气候变化和不同气候阶段的土壤侵蚀。通过野外调查,在西安白鹿塬区发现了黄土塬区罕见的3个层次的全新世中期古土壤,整个全新世黄土剖面可分为5层,表明黄土塬区全新世气候变化及沙尘暴活动与河谷地区一样可分为5个阶段。土层氧化物、微量元素、CaCO_(3)含量和磁化率测定结果显示,西安白鹿塬区全新世8500~6000年和5000~3100年古土壤发育时较10000~8500年、6000~5000年和3100年以来的黄土发育时夏季风活动强,降水量多,气候湿润,沙尘暴活动弱。中全新世8500~6000年间发育的S_(02)古土壤中Fe_(2)O_(3)和Al_(2)O_(3)有一定富集,该层土壤类型相当于黄棕壤,指示当时年平均降水量较现今多150 mm左右。虽然沙尘暴活动很弱的间冰期是黄土地层理论上的侵蚀期,但是实际上这一时期的土壤侵蚀很弱。全新世黄土的侵蚀主要发生在气候冷干时期,不是发生在温湿时期。全新世中期6000~5000年间的黄土侵蚀率一般大于堆积率,使得广大地区全新世中期的薄层黄土在绝大多数地区受到侵蚀而消失。全新世中期薄层黄土发育时气候变冷干引起的植被退化是当时土壤侵蚀加强和出现侵蚀期的原因。【Objective】This paper is oriented to reveal changes in climate,monsoon and sandstorm activity in Holocene in Xi’an area,to explore impacts of cold dry climate and warm wet climate on loess erosion and to define erosion period of the loess strata.【Method】Field surveys were carried out to investigate how loess and paleosol eroded in Holocene.Of the loess and paleosol,chemical compositions were determined with an X-ray fluorescence analysis instrument,CaCO_(3) content with the gas volume method,and magnetic susceptibility with a magnetic susceptibility instrument.【Results】Through the field investigation of 13 sample sites points at Bailuyuan of Xian,it is found that the mid-Holocene paleosol,rarely discovered in the loess plateau in the past,can be divided into three layers,including one layers of loess and two layers of paleosol.The loess and paleosol in the entire Holocene profile can be divided into five layers.The Holocene profile in Milucun displayed apparent changes in chemical composition and magnetic susceptibility and its loess and paleosol can also be divided into five layers,of which two paleosol layers are high and three loess layers low in SiO_(2),Fe_(2)O_(3),Al_(2)O and K_(2)O,and the five layers exhibit reverse trends in soil CaO.In the early mid-Holocene S02 paleosol layer,Fe_(2)O_(3) content varied in the range of 56.8~62.4 g·kg^(-1),and in the lower part of the paleosol it has been enriched up to 8.0 g·kg^(-1) and Al_(2)O_(3) up to 15.0 g·kg^(-1).The two paleosol layers are high in Rb,Ba,Ni,Sr and V(five trace elements)and the three loess layers are just the opposite,except in Sr.In the Holocene loess profile,CaCO_(3) varies similarly to CaO in content.The S02 paleosol layer is very low in CaCO_(3),demonstrating the feature of leaching soil being low in CaCO_(3).The two paleosol layers are high in low frequency magnetic susceptibility,while the three loess layers are low.【Conclusion】Various environmental indices indicate that in Beiluyuan the Holocene climate change and sandsto

关 键 词：全新世 黄土与古土壤 气候变化 全新世土壤侵蚀 西安地区 

分 类 号：P35[天文地球—空间物理学]